body {
    overflow-x: hidden;
    font-family: 'lucida Grande', Verdana, 'Microsoft YaHei';
    -webkit-font-smoothing: subpixel-antialiased;
}
.flex-center {
    display: flex;
    justify-content: center;
    align-items: center;
}
.bg-contain,
.bg-cover {
    background-repeat: no-repeat;
    background-position: center center;
}
.bg-contain {
    background-size: contain;
}
.bg-cover {
    background-size: cover;
}
.icon {
    width: 1em;
    height: 1em;
    vertical-align: -0.15em;
    fill: currentColor;
    overflow: hidden;
}
